Fibrotic Substrate Stiffness Enhances Endometriotic Epithelial Cell Motility

Fibrosis is a common pathological feature of inflammatory conditions across various organ systems, leading to a marked increase in matrix stiffness. The effects of substrate stiffness on benign epithelial cells in fibrotic microenvironments remain less well characterized compared with malignant cell types. We used an endometriotic epithelial cell line and polyacrylamide hydrogels with tunable stiffness to model mechanically driven single-cell and multicellular migration. We identified a biphasic relationship between substrate stiffness and epithelial migration, where substrates of intermediate stiffness best promoted cell speed, actin stress fiber formation, focal adhesion presentation, and spheroid expansion compared with the soft and very stiff gel substrates. Increasing cellular contractility on the soft substrate and decreasing contractility on the fibrotic stiffness substrate led to an increase and decrease in cell speed, respectively. These findings suggest a role for how fibrosis as a biomechanical state regulates epithelial cell migration during the pathogenesis of benign yet invasive conditions.